“I believe he messaged me, ‘Are you down to have some fun tonight?’ — and I decided to take advantage of it,” Ethan, who did not give a surname for fear of retaliation, told NBC.

“We started texting on there, and it got a lot more explicit,” Ethan said of at least 12 hours’ worth of chats on Tinder, Kik and Snapchat.

Ethan said he deliberately got enough info for police to track him — and even switched to airplane mode to prevent the man from getting automatic alerts when screenshots were taken.

San Jose cops say those screenshots show Davies “chatted about engaging in sexual activity,” leading to his arrest last Thursday following search warrants on his home and electronic devices.

The officer was booked into Santa Clara County Jail on charges of contacting a minor to commit a felony and put on paid administrative leave.

“This alleged conduct, if true, is in no way a reflection of all that we stand for as a Department, and is an affront to the tenets of our department and our profession as a whole,” his boss, San Mateo Police Chief Susan Manheimer, said in a statement.

Ethan, who said he was motivated by a female friend who told him she had been molested as a girl, insists his vigilante days are behind him.

“I was just looking to get someone. He just happened to be a cop,” he told NBC.